PROJECT SUMMARY/ABSTRACT Transplantation is an exciting field of clinical medicine with great potential for alleviating human disease. Because clinical transplantation is intimately associated with basic and translational scientists at Massachusetts General Hospital (MGH)/Harvard Medical School (HMS) in immunology and related disciplines, this field provides tremendous opportunities for training of scientists. MGH and HMS have outstanding teams of M.D. and Ph.D. scientists devoted to all aspects of transplantation, from the most basic molecular level to clinical transplantation, providing a unique environment to foster such training at the interface of clinical care and basic science. The purpose of our Program is to train young scientists and physician-scientists in basic and translational research, in the diverse lines of investigation related to transplantation biology, in this multi- disciplinary environment, with emphases on immunological mechanisms with translational applications. Participating faculty members with diverse but complementary research interests, a successful record of collaboration, and a commitment to training young investigators, have been assembled to provide trainees with exposure to topics related to transplantation immunobiology including immunogenetics, tolerance induction, antigen processing and presentation, bone marrow transplantation, regulation of lymphocyte development, pathology of graft rejection, complement biology, autoimmune disease, dendritic cell biology, chemokines and lymphocyte trafficking, B and T cell biology, regulatory T cells, mucosal immunology, gene editing, infection, cancer biology, and xenotransplantation. The major goal of this program is to develop outstanding independent investigators capable of addressing fundamental questions in the field of transplantation and the application of this knowledge to important clinical challenges. Pre-doctoral trainees will be selected from students currently enrolled in the Immunology Program at Harvard University's Division of Medical Sciences with an interest in pursuing thesis research in the field of transplantation immunology. Training for pre-doctoral students takes approximately 5 years, and students commit to thesis laboratories in the second year of graduate school. Pre-doctoral trainees already in transplantation-related research laboratories and distributed between students in their 3rd, 4th or 5th year of thesis research will be selected. Post-doctoral trainees currently holding a degree of MD, PhD, or MD/PhD will be selected with outstanding potential for careers in research and teaching and a commitment to independent investigation. Training will require 2-3 years. This program builds on our unique and dynamic environment to optimize individual training and mentorship experiences, by expanding into new areas of research, by recruitment of trainees and faculty from groups underrepresented in transplant research, to advance excellence in the field of transplantation.